


Edges All the Way Down

by daemonhart



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Anal Sex, Barbed Penis, Breathplay, Incest, Knotting, M/M, Pain, Plot What Plot/Porn Without Plot, Sibling Incest, Verbal Humiliation
Language: English
Status: Completed
Published: 2018-02-12
Updated: 2018-02-12
Packaged: 2019-03-17 06:01:25
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 706
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13652898
Author URL: https://archiveofourown.org/users/daemonhart/pseuds/daemonhart
Summary: [Drabble] Sometimes Sans just won't shut up, but that's nothing a little lack of air won't fix.





	Edges All the Way Down

Shit, shit, shit…Sans clawed at the bed beneath him and tore long rips through the blankets with pointed fingertips. Every time his brother pulled back, he could feel those rear-curving spines doing the same to the ectoplasm of his asshole. There was no flesh to tear, but it still hurt like hell. He tried to snarl back over his shoulder. Papyrus caught on at the first sign of resistance and shoved a hand down on the back of the smaller monster’s neck to force his face down against the mattress.

“Shut up, Sans…” Papyrus warned. “I don’t want to hear a word from you.” He could already feel his knot forming and he wasn’t going to risk going soft just because his subordinate couldn’t keep his mouth shut. The harsh clack of their bodies meeting overrode everything else, from the sloppy squish of the half-swollen bulb pulling free to Sans’ muffled, angry protests. The younger monster liked having sex like a lion -- roughly, frequently, and in short bursts. He didn't care how his older brother liked it. A bitch's role was to put out when their stud demanded. “Disgusting. You’re dripping everywhere. I expect you to clean this up once I’m finished with you.”

Sans wouldn’t have been able to talk back even if his mouth were free. His body tightened as he was berated. Pain, more pain. His cock shot a thin thread of pre when Papyrus needed to put some extra effort into yanking the knot free. It was too big to be using it to fuck; both of them knew, but neither cared. Drool tinged the off-white linens under Sans’ skull as he struggled to breathe to no avail. Each time he tried to lift his head, a gloved hand only shoved it down harder. The red pinpricks of his pupils rolled up. They flickered weakly in their sockets under the exertion of each thrust he took until at last they burned out.

His whole body went lax beneath Papyrus’ attack. A wicked sneer crossed the younger monster’s face. “Out already? Nyeheh, this is why you’ll never be great. You’re too weak…!” With free rein to do as he pleased, Papyrus held nothing back. On the way in, the thick bulb of his dick stretched his brother wide, and on the way out the spines dug in as though trying to force their victim to let him stay inside to avoid the pain. Only Sans would enjoy such a thing. Even now his body was responding without him, constantly dribbling pre, getting closer, closer, closer. Papyrus couldn’t hold himself in check. The next thrust hilted his jagged cock and his tall body curled down against Sans’ back. “Yessss, you worthless animal!” It didn’t matter that his sibling couldn’t hear him. All he needed was the rush that dominating him,  _humiliating_ him gave, saying the words and receiving no resistance. This piece of trash knew his place and dared not talk back!

Papyrus bit down hard on his tongue once orgasm coursed through him. His knot bulged completely and bound them together while he tugged back to give the spines purchase inside the hole he was so busy pumping full. His arms wrapped tight around Sans’ ribs to hold him still. Yet…no struggle came. Maybe he’d gone a little too far. With a grunt, Papyrus reluctantly let go of his breeder and gave him a look over. “Damned idiot,” he hissed. He gave a tug to make sure the tie wouldn’t break, then flopped onto his side, bringing Sans down with him. His arm draped over the other and tapped at his ribs. No response, but no crumbling bones, either. “I could’ve killed you, dumbass. Supposed to fuckin’ let me know if you’re suffocating.” His admonitions fell on deaf ears, but at least once he was done bitching, when he went silent…he heard his older brother drawing breath. Good. With a petulant grunt, he deigned to let his arm settle more gently over his fragile sibling. Stupid, weak Sans, passing out like that and missing the best part!

…Perhaps Papyrus felt a bit guilty, but he’d never say so.

…And maybe he’d make up for it by cleaning the bed later.


End file.
